The weight won't come down enough. Some things are always going to be heavier.

I'm sure they said that about disc brakes. Sort of two separate points here though - yes gearboxes will probably always be heavier than traditional derailleur set ups, but whether they will always be too heavy is surely not clear cut; don't you think they could at some point be made light enough?

The Honda system was only ever a derailleur in a can - literally an XTR mech, with a cassette set up in a can placed around the BB. It was heavier because of the extra chain lenghts you needed but you might be able to save weight in other areas e.g. on the rear hub and the wheel in general (no dish means stronger rear wheel).

Molegrips, despite not agreeing, do you still think they will be the future?